Apparatus for controlling rate of flow of a liquid



April 25, 1933- v, A. ROHUN APPARATUS FOR CONTROLLING RATE OF FLOW OF A LIQUID Filed Oct. 28. 1929 Patented pr. 25, 1933 UNITED STATES PATENT oFFlcE 'VICTOR A. ROBLIN, OF?HILADELPHIA, PENNSYLVANIA, ASSIGNOB. T0 COCHRANE COR- PORATION, OF PHILADELPHIA, PENNSYLVANIA,' A CORPORATION OF PENNSYL- VANIA APPARATUS Foa coN'rnoLLING RATE or' FLOW or A LIQUID Application led October 28, 1929. Serial No. 402,919.

My invention relates to improvements in method and apparatus for controlling the rate of flowof a liquid.

In accordance with my invention, the rate of flow of a liquid is controlled by varying fluid-pressure on a free surface of the liquid, such 'fluid-pressure being varied in accordance with variation in a condition such, forexample, as the rate of fiow of a fluid.

Further in accordance with my invention, improved apparatus of the character referred to is provided which is simple, reliable in operation, and which is adaptable to handle chemical solutions such as sulphuric acid without deterioration of parts or impairment of operation of the apparatus after long and continuous service.

My invention resides in the method and features of structure and combination of the character hereinafter described and claimed.

For the purpose of illustrating the invention, one embodiment thereof is shown in the drawing, in which Figure 1 is a fragmentary view of apparatus employing the present improved method of control and embodying the present structural improvements, one of the units making up the apparatus being shown `in section; and

Fig. 2 is an enlarged fragmentary view taken from Fig. 1.

The illustrated embodiment of the invention is useful where it is desired to supply chemical, such as sulphuric acid, toa mixing tank 10 supplied with raw feed water for a boiler by way of pipe line 11, the sulphuric acid being first supplied to the tank or container 12 and discharged therefrom by way of outlet connection 13 at a rate corresponding to the rate of flow of the liquid or raw feed water through line 11. The arrangement is such that increase in the rate of flow of raw feed water will be accompanied by a corresponding increase in the rate of discharge of the sulphuric acid solution from` outlet connection 13 into tank 10, while decrease in the rate of flow of feed water will be accompanied by a corresponding decrease in the rate of discharge of the solution from connection 13. The improved apparatus provides, therefore, that regardless of occurring.

variation in the'rate of supply of the raw feed water, there will always be addition of the proper amount of sulphuric acid solution toinsure a safe and proper relation between the sodium sulphate and sodium carbonate contents of the feed water supplied to the boiler from tank 10. vThe control apparatus, designated generally by reference numeral14, includes the container 12 provided with the closure or cover plate 15 and suitable valve mechanism 16 controlled .by Y

float 17 in such wise that sulphuric acid solution is admitted to the container by way of the supply or inlet connection 18 when the liquid in the container drops below thelevel 19 upon discharge of the solution from the tank by. way of connection 13.' In other words, the valve mechanism 16 and associated float 17 operate to maintain the liquid contents of container 12 substantially at the l level 19. An adjustable joint 17 of any suitable construction provides for angular ad. justment of the float arm if desired to place level 19 higher or lower, as the case might which is screwed plug 27 providing a seat yfor the vent valve 28 and having the vent or outlet opening 29. The bonnet or cap 30 is secured as shown to housing 23 and carries the adjustable screw 31 arranged to engage the end of the valve stem '32 in such wise that upon upward movement of plate 24 the valve seat is moved away from valve 28, the compression spring 33 operating at all times to urge valve 28 upwardly with respect to the valve seat and into seating relation therewith.

Downwardl movement of plate 24 is accom- I panied by similar movement of valve seat 27 downwardly with respect to valve 28 to decrease the effective vent opening, while upward movement of plate 24 has the opposite effect and causes increase of the effective vent openin The ellows 34 and 35 are disposed between base 21 and plate 24 and one within the other, as shown, and are secured to the base and plate to provide chambers 36 and 37. V

The bellows 38 is disposed about vent tube 25 between plate 24 andthe top of housing 23. One end of bellows 38 is secured to plate 24, the other end being secured to the end piece 39 extending through the top of housing 23 and receiving the nut 40 which operates to clamp the end piece securely tothe housing. 1 The vent tube 25 passes loosely through end piece 39 to permit free upward and downward movement of the tube with plate 24 and to permit free Vfluid-How between the atmosphere exterior of the apparatus f and chamber 41. l

The chamber 41, interior'of bellows 38, is therefore always under atmospheric pressure, the loose it between vent tube 25 andend piece 39 providing against any retarding or dash-pot action of bellows 38 to interfere With upward and downward movement of plate 24 under the iniiuence of forces hereinafter referred to. The connection 42 provides communication between chamber 43 and supply line l1 at the point 44 on the up-stream side of a suitable orifice plate 45. The connection 46 provides communication between chamber 37 and supply line 11 at the point 47 on the down-stream side of orifice plate 45.

An air pressure supply connection 48 extends between cover-plate 15 and housing flange 22 in the same manner as connections 42 and 46, but unlike those connections extends entirely through 21 to supply air or other gas under pressure to chamber 36 and by way of opening 20'to the interior of container 12. The air flow is reduced to a suitable value below the capacity of the escape valve 28 by an orifice plate in the supply.

connection 48, or the connection itself may be-of small diameter. As hereinafter eX- plained, the release of air from chamber 36 is controlled by valve 28 to maintain a pressure which balances the differential pressure on plate 24, which' in practice, never exceeds the pressure effecting flow of the acid solution to container 12 through connection 18. After balance is effected, air is released by valve 28 at the same rate that it is supplied, which maintains the balance between the air pressure and the existing differential pressure.

Housing 23 may be provided with a vent plug 49 which is removed during installation of the apparatus to permit complete displacement of any entrained air in chamber 43 by the liquid which will flow into this chamber by way of connection 42, after 24 to permit iow of such entrained air from'` chamber 37 into chamber 43 and thence to atmosphere by way of the opening' for plug. 49. The pressure on the under surface of' plate 24 between `bellows 34 and 35 will,-l

therefore, be substantially the same as the pressure at point 47 in line 11, and will follow closely any variation in the pressure at point 47. The ventV opening in plate 24 is made just large enough for the purpose explained, and does not 'permit any appreciable liquid-flow between chambers 37 and 43 such as might otherwise prevent proper movement of plate 24 responsive to variations in pressure conditions in these chambers.

YA tube 50 is threaded at its upper end into plate 24 and arranged as shown in alignment with vent tube 25, the diameter of the tube being appreciably less than that of opening 20 to perinitfree fluid flow between chamber 36 and container 12.

The operation of the improved apparatus is as follows. The floating plate 24 is acted upon by a downwardly directed force on its upper face equal to the area of that portion of the plate extending outwardly beyond bellows 38 multiplied by the liquid pressure at point 44 in line 11. This plate is also acted upon by an upwardly directed force equal to the area of that portion of the plate intermediate bellows 34 and 35 multiplied by the liquid pressure at point 47 in line 11. This plate is also acted upon by an upwardly directed force equal substantially to the area of the plate between tube 50 and bellows 34 multiplied by the' air pressure in chamber 36 and container 12. As is well known, the difference between pressure conditions at points 44 and 47 in supply line 11 is a measure of the rate of liquid flow in the line. From the foregoing it will be seen that `the floating plate 24 is responsive to the joint influence of fluid-pressure conditions in container 12 andthe condition of the rate of liquid-flow in line 11.

For any given rate of liquid-flow in line 1l, within the operating; range, there will obviously be a force acting downwardly on plate 24 due to the pressure in chamber 43 and a force acting upwardly on theI plate due to the pressure in chamber 37, the downwardly directed force being greater than the upwardly directed force. in amount corre sponding to the rate of liquid-flow in line 11. This difference is balanced bythe upwardly directed force on plate 24 due to the air pressure in chamber 36: The air pressure acting on the free surface of the sulphuric acid solution in container 12 operates at the same time to force the solution from the container at the proper rate by way of outlet connection 13. Upon increase in the rate of flow of the raw feed water in supply line 11, the pressure in chamber 43 will increase correspondingly over the pressure in chamber 37, and the floating plate 24 forced downwardly to effect closing operation of .the valve means 27-28, whereupon the air pressure in container 12 and chamber 36 is permitted to build up until the upwardly directed force on plate -24 due to the pressure in chamber 36 is increased suiiiciently to balance the increased difference between the forces due to the pressures in chamberse43 and 37 at which time the valve means 27 28 reopens to permit escape of air as fast as supplied to maintain the higher air pressure. The airpressure in container 12 therefore increases bysuch amount as to provide.

for discharge of the solution by way of outlet connection 13 at a correspondingly greater rate to supply the greater amount of raw feed water now being discharged into mixing tank 10 with a correspondingly greater amount of sulphuric acid solution.

Upon decrease in the rate of flow of raw feed water in supply line 11, the action is just the opposite, that is, the difference between the respective pressures in chambers 43 and 37 will decrease to cause unbalancing of the forces acting on plate 24 and corresponding upward movement of the same to effect opening operation of the valve means 27-28 whereby the air pressure in chamber 36 and container 12 is permitted to drop until the forces acting on plate 24 are again balanced, at which time the valve means 27-28 v in a new position permits escape of air as fast as supplied to hold the air pressure on the free surface of the solution in container 12 at a lower value. Accordingly, the solution is forced from container 12 at a lower rate corresponding to the lower rate at which the raw feed water is being discharged into tank 10 from supply line 11.

The action, therefore, is such that increase in the rate of discharge of the raw feed water into mixing tank 10 is accompanied by a corresponding increase in the rate of discharge from outlet connection 13 of the sulphuric acid solution into tank 10. while decrease in the rate of discharge of the raw feed water into tank 10 is accompanied by a corresponding decrease in the rate of discharge of the sulphuric acid solution into thetank, the proportion being maintained substantially constant such that the proper relation between the sodium sulphate and sodium carbonate contents is maintained. In other words, in the disclosed embodiment of the invention, the control apparatus proportions the How of chemical to the flow of raw feed water by maintaining a liquid pressure on orifice 55' which is .proportional at all times to the differential pressure on orifice 45 in the feed water line.

Where' the apparatus is to handle chemicals such as sulphuric acid solution, the tank and associated connections will be lined with suitable material known to be resistive to the action of acid. The valve mechanism 16 will, in such case, also be made of suitable acid-resisting material. By making the air supply connection 48 at the point shown, that is, above cover plate 15 and at a point within chamber 37, there will always be an air pocket in bellows 34 and there will be constantflow of air from chamber-36 into container 12 by way of opening 20. Acid fumes are therefore prevented from entering chamber 36 by way of opening 20. The bellows 34 may therefore be made of copper or other suitable material, and need not, necessarily, be made of acid-resistive material.

If, for any reason, the valve mechanism 16 should fail to shut olf the supply of acid solution from supply connection 18 at conditions whereat there is no flow of raw feed water in line 11, container 12 will lill up with the solution and the same forced upwardly through tubes 50 and 25 and out through vent opening 29 from which the escaping solution will drop down upon deflector 26 and into the basin 51 from which it will iiow by way of a suitable connection l52 to a. selected point where the discharge of the solutionfrom this connection will be observed. The connec-y tion 52, therefore, provides indication of the condition of flooding of the control apparatus due to possible failure of valve mechanism 16 to operate properly. This, of course, is merely a safety measure. Should the apparatus be flooded for the reason explained, the acid solution escaping by way of vent opening 29 is prevented by deiiector 26 from passing downwardly along vent tube 25 and collecting in chamber 41. Further. if the apparatus should be flooded, the acid will be prevented from rising into chamber 36 by reason of the air pocket therein.

In installing the apparatus, vthe supply of liquid to line 11 is shut oli", at which time the pressure in chambers 43 and 37 will be equal. The screw 31 is then adjusted to position vent valve 28 such that the air pressure in chamber -36 and container 12 is just sufficient to force l eo.

solution discharged from connection 13 at the proper rate under the influence of the increased air pressure condition on the free surface of the solution in container 12.

The apparatus may be calibrated by selecting the plug 54 with an orifice 55 of such size as to provide for discharge of the Chemical at the proper rate for the known concentration thereof and for a given rate of discharge of raw feed Water into tank 10. For this purpose, a-` number of the plugs 54 may be provided, each having an orifice of different diameter than the other. y

Variation in the proportion of chemical supply to feed Water supply may also be effected by increasing or decreasing the concentration of the chemical solution.

From the foregoing it will be seen that an improved method has been provided for controlling the iow of a liquid in accordance With variation in a given condition, the method consisting in varying the fluid-pressure on a free surface of the liquid in accordance With variations in a condition. For example, in the embodiment of the invention disclosed,

the air pressure on the free surface of the chemical solution in container 12 is varied in accordance with variations in the condition of fluid-How in supply line 11. It Will be appreciated, in this connection, that such condition need not necessarily be a condition of iiuid-flow in a pipe line, but might be any variable condition in accordance With Which it is desired to control the rate of flow of a liquid, such, for example, as the rate of flow of the chemical solution throughoriice 55. Further, it will be seen that air is supplied to .the apparatus at a substantially constant rate, and d'scharged at the same rate by Way of vent valve 28, the vent valve being adjusted to vary the backpressure and, accordingly, the pressure on the free surface of the liquid "i in container 12. The dimensions are such that when vent valve 28 1s 1n its extreme open position, discharge of air from the apparatus ata rate greater than the rate of air supply v to the apparatus by Way of connection 48, is

til)A possible. v

It will, further, be seen that improved apparatus of the character referred to has been provided which is accurate and immediately ,I 'f responsive to variations in the rate of iow in feed Water supply line 11, which has few parts With which the liquid in container 12 comes into contact, and Which is dependable and Will operate satisfactorily over a long iarperiod of continuous service and Without the necessity of attention or adjustment.

.'.RWVhile the present invention has been dislclosed as embodied in a system or apparatus more particularly adapted toprovide for supply of a chemical solution proportional "tolthe supply of raw feed Water for a boiler, it vrwill be appreciated that the invention is of'much broader adaptation, and that the same might be embodied in other systems Where there is thesame general requirement, that is, Where the rate of flow of a liquid is to be controlledin accordance with variations in a certain condition. It will be appreciated, further, that in the particular embodiment of the invention disclosed, various changes might be made such as in the size, shape and arrangement of the parts Without departing from the spirit of the invention or the scope of the claims.

The invention claimed is:

1. In apparatus of the character described, a closed container, means operable to provide for supply of liquid to said container and maintenance of the liquid contents at substantially a predetermined level, a Huid-pressure supply connection communicating with said container, valve means operable to control fluid pressure conditions in said contain'- er, and means responsive to fluid-pressure conditions in said container and operable in accordance with such conditions to control operating action of said valve means.

2. In apparatus of the character described, a closed container, means operable to provide for supply of liquid to said container and maintenance of the liquid contents at substantially a predetermined level, a fluid-pressure supply connection communicating with saidcontainer, valve means operable to control fiuid-pressure conditions in said container, and means responsive to fluid-pressure conditions in said container and operable upon increase in such conditions to eect opening operation of said valve means and operable upon decrease in such conditions to effect closing operation of said valve means.

3. In apparatus of the character described, a closed container, valve means for controlling fiuid-pressure conditions in said container, and means responsive to fluid-pressure conditions to Which said apparatus is subjected and operable in accordance with such conditions to control operating action of said valve means, said valveiiac'tuating means including bellows disposedonevvithin the other.

`4. In apparatus of thecharacter described, a closed container, val'vefmearns? for-controlling fiuid-pressure conditionsy in said container, and means responsive to fluid-'pressure conditions to -Which sa'i'd'apparat'us is sub'- jected and operable in A' ordance Withsuch conditions to control op ting"`actin of said valve means, said val'v tii'atin'g means including a plate, a vent rb""carried'by said plate and communicating 1th said'container, bellows secured to saidflplat'e communicating with said container, second bellows secured to said plate an d' sedab'ou't'said first-named bellows` edgre'vl'ation with respect thereto, a caslng ncloisiiigfsaid bellovvs and having through which one end of said ventjtubefloo'sely passes, and third bellows disposed about' sa i and secured at is respective ends to said plate and said casing, said valve means carried by said end of said vent tube.

5. ln apparatus of the character described, a liquid supply line, a closed container, means operable to provide for supply of liquid to said container and maintenance of the liquid contents at substantially a predetermined level, a iuid-pressure supply connection communicating with said container, valve means operable to control fluid-pressure conditions in said container, and means responsive to the joint inuence of duid-pressure conditions in said container and atdierent points in said line and operable in accordance therewith to control operating action of said valve means.

6. ln apparatus of the character described,

a liquid supply line, a closed container, means operable to provide for supply of liquid to said container and maintenance oi` the liquid contents at 'substantially a predetermined level, a Huid-pressure supply connection com municating With said container, valve means operable to provide a vent for said container,

and means responsive to conditions of inf creased liquid-flow in said line and operable thereupon to eiiect closing operation of said valve means and responsive lto conditions of decreased liquid-dow in said lineand operable thereupon to effect opening operation of said valve means.

7. A system for adding a liquid reagent to liquid under treatment comprising a closed container for said reagent, an outlet therefrom for discharge into said liquid under treatment, means for continuously supplying air under pressure to said container to produce a pressure eii'ecting discharge of said reagent, and means responsive .to rate oli flow of said liquid under treatment controlling release to the atmosphere of said air from said container at a rate to maintain a pressure therein of magnitude effecting flow of reagent proportional to flow of liquid under treatment.

8. A system for adding a liquid reagent to liquid under treatment comprising a closed container for said reagent, an outlet therefrom for discharge into said liquid under treatment, means for continuously supplying gas to said container to produce a pressure eiiecting discharge of said reagent, and means having eXpansible and contractable portions responsive to rate of How of said liquid under treatment controlling release of said gas from said container at a rate to maintain a pressure therein of magnitude effecting flow of reagent proportional to How of liquid under treatment.

9. A system for adding a liquid reagent to liquid under treatment comprising a closed container for said reagent, an outlet therefrom for discharge into said liquid under treatment, means for continuously supplying ment.

VITOR A. RHLIN. 

